get_signup_session

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, non-destructive, open-world semantics, but the description adds real behavior: this is a polling call on a public session, it exposes billing nuance (card saved, nothing charged today, prior-trial accounts charged at checkout), and it constrains how results should be surfaced to users. Return shape is still not described, keeping it below a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three compact sentences, front-loaded with the core action and followed by usage and narration constraints. The final sentence about not narrating curl/HTTP plumbing is slightly tangential to invocation but earns its place as a behavioral constraint.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter read-only polling tool with no output schema and fully covered parameters, the description supplies enough: what it polls, the states it surfaces (trial, password setup, agent access), and the billing edge case. Nothing needed to call it correctly appears to be missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so session_id's origin (returned by start_signup, usually the Stripe checkout session ID) and the debug flag are already documented in the schema. The description only loosely reinforces the session_id provenance and adds no format or usage detail beyond it, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Poll a public posterly signup session') and ties it to the originating sibling ('created by start_signup'), so the agent can distinguish it from start_signup or get_agent_signup_info without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear use context — narrating trial, password setup, and agent access status before an API key exists — plus the edge case that an account with a prior trial is charged at checkout. It does not explicitly rule out or name alternatives such as get_agent_signup_info, so it falls short of a full when/when-not statement.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.